System for use in controlling a hydrocarbon production well

ABSTRACT

A system for use in controlling a hydrocarbon production well has a: computer at a control location remote from a well tree of the well. A processor at the well tree applies control signals to and receives signals from devices of the well tree. The processor also receives further signals associated with the operation of the well. A bi-directional communication link extends between the remote computer and the well tree processor. The well tree further has a communications router coupled with the processor and receiver, for multiplexing the signals from devices at the well head and the further signals on to the bi-directional link.

CROSS-REFERENCE TO RELATED APPLICATION

This application claims the benefit of United Kingdom Patent ApplicationNo. 0228203.6, filed on Dec. 3, 2002, which hereby is incorporated byreference in its entirety.

TECHNICAL FIELD OF THE INVENTION

The present invention relates to a system for use in controlling ahydrocarbon production well.

BACKGROUND OF THE INVENTION

In the subsea fluid extraction industry, communication is requiredbetween a control centre and well heads located on the seabed.Traditionally, the control centre is located on a platform or vessel inrelatively close proximity to the well complex. In some cases, thecontrol centre is located on land, where the distance from the controlcentre to the well heads can be much greater and could be typically 200km. High capacity communication systems, typically involving opticalfibres, allow the possibility of much higher data rates between thesubsea and surface facilities, which further enables methods ofconnecting subsea data sources (e.g. sensors), particularly thosegenerating large quantities of data such as microseismic sensors and TVcameras.

A conventional approach is to use a standard subsea bus at the well headends of a data transmission system to connect such various subsea datasources. This means that any other party providing equipment to thesystem has to interface with the bus and conform to its protocol, datarates and bus standards. Since different manufacturers have standardequipment with interfaces to a multiplicity of protocols and data rates,substantial costs are involved in adapting these interfaces to suit thestandard bus. Furthermore, since this data is time multiplexed on thebus, the data rates are also somewhat limited such that some desirable,high bandwidth, data transmissions, such as digital video signals,cannot be economically transmitted.

FIG. 1 shows a conventional system for the communication of data betweensubsea well trees and a surface facility. Mounted on each of a number ofsubsea well trees (not shown) is a subsea electronics module (SEM) 1including a SEM processor 2, which handles at a port 3 data fromconventional tree sensors such as pressure and temperature and at a port4 data for control of devices such as valves and fluid control chokes,there being a port 5 for a standard interface for data from other subseadata sources. The SEM processor 2 communicates bi-directionally with asurface facility computer system 6 (on shore or on a platform forexample) via a modem 7 housed in the SEM 1, a communication link 8 and amodem 9 housed in a surface modem unit (SMU) 10 at the surface facility.The communication link 8 enables communication with the SEMs of otherwell trees and at some or all of the well trees there is systemduplication to improve system availability—thus in FIG. 1 there areshown two SEMs (SEM A1 and SEM B1) for a particular well tree, SEM A2and SEM B2 representing duplicate SEMs for another tree.

When the surface computer 6 is located at a considerable distance, suchas, typically, 200 km from the well complex, a fibre optic link is usedas link 8 to transmit data between the or each SEM at a well tree to thesurface computer 6. Nevertheless, the data from other sources at port 5needs to be adapted to the protocol, data rates and other standards usedfor the communication of control information and sensor information.

SUMMARY OF THE INVENTION

According to the present invention, there is provided a system for usein controlling a hydrocarbon production well, comprising computing meansat a control location remote from a well tree of the well. The systemalso has a well tree means has a processing means for applying controlsignals to and receiving signals from devices of the well tree. The welltree means includes means for receiving further signals associated withthe operation of the well. A bi-directional communication link existsbetween said computing means and said well tree means.

The well tree means further comprises a communications router coupledwith said processing means and said receiving means, for multiplexingsaid signals from devices at the well head and said further signals onto said bi-directional link. The bi-directional link could comprise afibre optics link.

There could be a plurality of such well tree means at respective welltrees, there being a distribution means between said bi-directional linkand the well tree means for distributing control signals to said welltree means and receiving multiplexed signals from said well tree means.

The signals from devices at the well head and further signals could havedifferent protocols and different data speeds. The further signals couldinclude video signals.

The present invention also comprises a combination of a system accordingto the invention providing a first communication channel, and a furthersuch system, providing a second communication channel for use if thefirst channel fails.

BRIEF DESCRIPTION OF THE DRAWINGS

The present invention will now be described, by way of example, withreference to the accompanying drawings, in which:

FIG. 1 is a diagram of a prior art form of system for use in controllinga hydrocarbon production well;

FIG. 2 is a diagram of an example of a system according to the presentinvention;

FIG. 3 is a diagram of another example of the present invention; and

FIG. 4 is a diagram showing part of an alternative to what is shown inFIG. 3.

DETAIL DESCRIPTION OF THE PREFERRED EMBODIMENT

FIG. 2 (in which items which correspond with those in FIG. 1 have thesame reference numerals as in FIG. 1) illustrates a system according toan example of the invention, showing linking from a surface computer 6to a well tree. The surface computer 6 at the control centre (on shoreor on a platform for example) sends and receives data to and from asurface modem unit (SMU) 10 which houses a modem 9. This modem 9transmits and receives data via a communication link 8. The other end ofthe communication link 8 connects to the well head tree which carries asubsea electronics module (SEM) 11 which houses a modem 7 which is asimilar device to the modem 9 and performs the opposite function. Themodem 7 has an electrical output/input, which is connected to acommunications processor 12 which functions as a communications router(or intelligent multiplexer), also housed in the SEM 11. Thecommunications router 12, has a multiplicity of inputs/outputs, therebeing an interface with a conventional SEM processor 2 (having sensor,control and standard interface ports 3, 4 and 5) and also interfaces 13which interface with other ‘private’ standard interfaces known asvirtual links. The interfaces are effectively ‘star connected’ ratherthan the conventional ‘highway connected’ and virtually any protocol anddata rate can be handled, limited only by the router 12, speed and thefinal limitation of the bandwidth of the communication link 8 and itsmodems 7 and 9. Typically, the link 8 could be about 200 km in length,data being transmitted via it at typically 10 Mbits/sec. The software inthe router 12 is flexible and handles, by multiplexing, the data andprotocol of the ‘private’ interfaces, as required for the systemconfiguration, to permit high speed communication to and from the modem7, thereby providing virtual links between the surface and subseaequipment. The SEM processor 2 handles the conventional control ofsubsea devices, such as valves and chokes, to control the fluidextraction process. It also handles local logging and processing of datafrom the tree sensors, its main functions being to acquire data from thesensors and assemble it into a format that can be transmitted to thesurface computer and to issue control signals to valves and fluidcontrol chokes for example.

Typical of the above-mentioned private, standard interfaces are theintelligent well system interface, (IWS) (an Ethernet interface), andothers as shown in FIG. 2 which are well known in the industry, as wellas interfaces to devices such as level sensors, microseismic sensors andfluid quality sensors. Due to the fact that the system configurationallows high bandwidth utilisation of the communication link 8, typicallya fibre optic link, it is possible to transmit compressed video. Thisallows the fitting of cameras to the subsea well head, to permit visualinspection of the tree without the need for expensive diving operationsor the use of a remote operation vehicle (ROV). This will have majorbenefits to the well operator who, in the past, has had to rely onsensor information to prompt the deployment of divers or a ROV to effecta visual inspection, but can now have a continuous visual inspectionfacility.

FIG. 3 (in which items which correspond with those in FIG. 2 have thesame reference numerals as in FIG. 2) shows a typical full systemimplementation to handle communication between a control centre and asubsea well complex, and providing high availability through dual duplexredundancy. The figure shows a high end application with a large amountof redundancy and long distance offsets with a subsea centraldistribution system arrangement that sits between a surface computer andwell head control modules.

Two separate communication channels are provided, A and B, to provide100% redundancy. Describing channel A, a surface computer 6 at thecontrol centre (on shore or on a platform for example) feeds andreceives data to and from an SMU 14 which houses two bi-directionaloptical modems 15 and 16.

The optical modems 15 and 16 interface with respective ones of a pair ofoptical fibres 17 and 18, which terminate near to a well head complex ata communication electronics module (CEM) 19 typically located on theseabed. Typically, the communication link provided by the optical fibrescould be about 200 km, data being transmitted via them at typically 10Mbits/sec. The CEM 19 enables interfacing of many wells in the localitywith the optical fibres 17 and 18. The use of two optical fibresprovides further redundancy and thus greater communications reliability.The CEM 19 houses another two bi-directional optical modems 20 and 21coupled with respective ones of fibres 17 and 18 and which outputelectrical signals to a communications router 22. The communicationsrouter 22 interfaces with electrical modems, of which three, 23, 24 and25 are shown, by way of example, each of which interfaces with a modemof a SEM at a well tree. Thus, for example, the modem 23 interfaces witha modem 7 of a SEM 1 via a communication link 26 and with the modems atother trees within the group via a communication link 27 and modems 24and 25 interface with modems at other groups of trees via communicationlinks 28 and 29.

FIG. 3 also shows a duplicated identical channel B for use instead ofchannel A for further reliability. In the event of failure of bothchannels, rudimentary communication is provided by a link 30 from thecomputer 6 of each channel, a low speed communications modem (LSCM) 31,a back-up communication link 32 (typically operating at 1.2 kbits/sec)and a link 33 for each channel, each link being coupled by a LSCM 34 tothe communications router 22 of the respective channel.

It should be noted that each of modems 23, 24, 25, etc. and each of thecorresponding modems at the well tree SEM's, may, alternatively, be ofthe form that communicates via the electrical power supply to the tree,i.e. a comms-on-power (COP) type of modem.

FIG. 4 shows part of an alternative to the system of FIG. 3, items whichcorrespond with items in FIG. 3 having the same reference numerals as inFIG. 3. Instead of a single back-up communication link, each channel hasits own back-up communication link 35 (typically operating at 1.2kbits/sec), being a link which provides subsea power from a 3-phase, 3kv supply and each channel having a respective LSCM 36 instead of therebeing a single LSCM 31 as in FIG. 3. In FIG. 4, modems 23, 24 and 25 areCOP modems.

While the invention has been shown in only a few of its forms, it shouldbe apparent to those skilled in the art that it is not so limited but issusceptible to various changes without departing from the scope of theinvention.

1-8. (canceled)
 9. A system for remotely controlling subsea equipment,comprising: a subsea well complex; a surface computer facility; at leastone communicating device at the well complex; a modem at the wellcomplex for communicating with the computer facility; a communicationsrouter at the well complex coupled to the modem; a communications linkextending between the computer facility and the modem; a processing coreat the well complex coupled to the communications router for performingcontrol and monitoring functions at the well complex; the communicatingdevice being coupled directly to the router and by-passing theprocessing core for communicating with the computer facility.
 10. Thesystem according to claim 9, wherein the communicating device comprisesa sensor.
 11. The system according to claim 10, wherein the sensorcomprises a video camera.
 12. The system according to claim 9, furthercomprising a sensor coupled to the processing core for performing themonitoring function.
 13. The system according to claim 9, wherein thecommunicating device communicates with the router pursuant to a selecteddata protocol, and the processing core communicates with the routerpursuant to a different data protocol.
 14. The system according to claim9, wherein the at least one communicating device comprises first andsecond communicating devices and wherein the first communicating devicecommunicates with the router pursuant to a selected data protocol, andthe second communicating device communicates with the router pursuant toa different data protocol.
 15. The system according to claim 9, whereinthe communication link comprises an optical fiber.
 16. A subseaelectronics module for removing controlling subsea equipment,comprising: at least one subsea communicating device; a subsea modem; asubsea communications router coupled to the modem; a subsea processingcore coupled to the communications router for performing subsea controland monitoring functions; the communicating device being coupleddirectly to the router and by-passing the processing core.
 17. Thesystem according to claim 16, wherein the communicating device comprisesa sensor.
 18. The system according to claim 17, wherein the sensorcomprises a video camera.
 19. The system according to claim 16, furthercomprising a sensor coupled to the processing core for performing themonitoring function.
 20. The system according to claim 16, wherein thecommunicating device communicates with the router pursuant to a selecteddata protocol, and the processing core communicates with the routerpursuant to a different data protocol.
 21. The system according to claim16, wherein the at least one communicating device comprises first andsecond communicating devices and wherein the first communicating devicecommunicates with the router pursuant to a selected data protocol, andthe second communicating device communicates with the router pursuant toa different data protocol.
 22. The system according to claim 16, furthercomprising an optical fiber link connected between the subsea modem anda surface computer facility.
 23. A method for remotely controllingsubsea equipment at a subsea well complex from a surface computerfacility, the method comprising: (a) providing a subsea processing core;(b) providing a subsea communicating device; (c) monitoring andcontrolling subsea equipment with the processing core and routing asignal in response thereto from the processing core to the surfacecomputer facility; and (d) routing a signal from the communicatingdevice directly to the surface computer facility and by-passing thesubsea processing core.
 24. The method according to claim 23, whereinstep (d) comprises routing a signal corresponding to a sensed parameter.25. The method according to claim 23, wherein step (d) comprises routinga video signal.
 26. The method according to claim 23, wherein steps (c)and (d) are performed using different protocols.
 27. The methodaccording to claim 23, further comprising sensing a subseacharacteristic and providing a signal to the processing core.
 28. Themethod according to claim 23, wherein steps (c) and (d) are communicatedto the surface computer facility via an optical fiber.